Photo: flickr/Moyan Brenn
According to this study, you can add horses to the short list of animals that can tell if you're happy or angry (which currently includes only dogs). To test this, the authors showed horses photos of either happy or angry faces and tracked whether the horses looked to the left or right -- apparently, looking left tends to be associated with negative stimuli. The researchers found that the horses looked left more often and their heart rates sped up when viewing angry human faces, indicating that they were identifying the appropriate emotions. Our biggest criticism of this study? They failed to include a "why the long face?" joke.
Functionally relevant responses to human facial expressions of emotion in the domestic horse (Equus caballus) "Whether non-human animals can recognize human signals, including emotions, has both scientific and applied importance, and is particularly relevant for domesticated species. This study ...